This invention has relation to a furnace designed to burn wood and to provide forced hot air heating for a home or other building enclosure.
It is known to provide a furnace for burning wood with an upper combustion chamber and a lower combustion chamber or fire box and with vertical smoke passageways separating the chambers. Such structures have also been provided with spaced outer jackets completely surrounding the combustion chamber except for a fire door, a lower draft opening, an upper cleanout opening for the upper combustion chamber, and a stack extending out from the top of the upper combustion chamber. Forced air has been provided between this jacket and the combustion chambers by the use of a centrifugal fan set in a blower compartment beneath the fire box and discharging into the air passageway between the outer shell and the fire box. However, the combustion chambers of such prior art structures have been constructed of sheet metal with sharp angular breaks and bends therein. Such prior art structures have suffered from the difficulty that uneven heat spots are created, causing the metal jackets and the metal of the combustion chambers to warp out of shape and fail under ordinary usage and service.
An earlier model of wood burning furnace constructed as set out above had the wood fire laid directly on the bottom of the lower combustion chamber, with the ashes and other residue being removable only by scraping the residue forward and shoveling it out of the fire door or out of the draft opening. This usually or most often resulted in the necessity for rekindling the fire after every such emptying of ashes.
In order to overcome these deficiencies, and to produce a more efficient wood burning furnace, the furnace of the present invention was developed.
No preliminary search has been made in the records of the U.S. Patent and Trademark Office in regard to this invention. In addition to the prior art described above, applicant is familiar with the log furnaces manufactured and sold by Earth Stove Northwest of P.O. Box 549, Tualatin, Ore. 97062. A photocopy of their brochure identified as 2/792M PP is presented herewith together with a photocopy of a phantom outline drawing of their model LFV 200 furnace. It is evident that the rectilinear construction of the top of their stainless steel fire box and of their rectilinear stainless steel heat exchanger take this structure outside of the concept of the present invention.
Neither applicant nor those in privity to him know of any prior art structures which anticipate the present invention and they know of no prior art which anticipates any of the claims made herein.